Piston



f Aug. 4, 1925.

A 1,548,329 A. NELSON PIsToN Filed June 2. 1923- 2 Sheefs-Sheet l \\Q\\\` Yi@ Aug. 4, 1925. 1,548,329

A. L. NELSON PIsToN` i Filed June 2. i923 2 Sheets-Sheet 2 'PTH-1- 1 Wg-5% Patented Aug. 4, 1.925.l y f UNITED' STATES PATENT omer..

A DOLPH L. OF INDIANAPOLIS; INDIANA.

ISTGN.

Application nea 'June a, 1923. serial No. 643,073.

` heat on the head. ln some instances also ing process. 'llhe advantages of such a conthe skirt may be made of different material from the head, for example the head may be made of cast iron to minimize wear in the ring grooves while the skirt may be of a relatively light and soft alloy.

The main object of the invent-ion is to provide a iston in which the skirt shall be relatively ee from contraction and expansion being when cold in a condition of ystrain which is relieved when the skirt warms up but due to such strain there is very little actual increase ,in diameter during the warmstruction in preventing or decreasing the piston slap when'the engine is cold and in insuring themaintenance of a lilm of oil between the piston and the cylinder at all times will be ,obvious to those skilled in the Subsidiary purposes are to provide eilicient means for holding together the separate head and skirt, to `provide meansv insuring correct alinement of the head and the skirt, and to provide improved means for preventing access of oil to the cylinder above the piston. Other purposes will appear upon consideration of the subjoinedl description.

Referring tothe accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts,

Figure 1 is a central vertical section of one form of my invention, t Figure 2, a horizontal section of `Figure l. immediately above the upper strut,

Figure 3, an inverted plan of Figure l,

Figure a, a vertical central section of another form of my invention, on line 1 -4 of Figure 5, K f

Figure 5, a section at'right angles to Figure a Fie 6, a detail ef the upper strut in Figures a and a, and

" the skirt.,

Figure 7, a detail of a lmodified strut. lin the drawings reference character 10 indicates the head of the piston which is secured to the skirt 11`by means of bolts 12 engaging threaded openings in bosses 13 on the head and fitting loosely in openings through bosses 13 on the skirt. These bolts also extend through openings in the hollow piston pin 14 which is mounted in bearings `011 the extensions 13 and is held in iixed position by the bolts.

The skirt has an annular rim at 15 extending upwardly to surround the lower portion of the head and a strut 16, preferably made of a steel stamping, is located between the head and the adjacent part of the skirt, said 'strut fitting closely within the rim 15 except at the parts nearestto the bolts y12 where the strut is relieved to a slight extent as at 17 to allow for cases where the cylinders go out of round. It will be seen that the strut acts as a rigid member to prevent contraction of the skirt in a direction transversely of the piston pin whereas a slight contraction is permitted longitudinally of the piston pin by the relief at 17, 17. rlfhe strut 16 has a central aperture adapted to be engaged by a depending hollow boss 18 on the head ofthe piston. rlhis boss fits closely within the opening and is of assistance in locating the head in alinement with The strut is also provided at each side of a line passing through bolts 12 with groups ofopenings 18 arranged in semicircles.

, f Beneaththe piston pin is a second strut at 19 in similar marmer to strut 16. The

piston pin is flattened near its ends for secure engagement by the lower strut and washers 20 are placed between the heads of the bolts and the lower strut, these washers each having an arcuate surface at one side as indicated at 21 to bear against the inner surface of the skirt.

The skirt is slitted at intervals from above' and below as shown at 22 and 23, these slits serving a double purpose in that the upper slits provide a means for the excess Y expansion while the contraction upon cooling will .proceed in the reverse fashion by the gradual narrowing of the tongues but unaffected by any considerable radial .move ment in the skirt. It should be noted also that the separation of the .skirt from the head tends to insulate the skirt from the high temperature of the head, which effect is augmented by the material of the upper strut which should be selected partly for its relative impermeability to heat.

In the form of the invention shown inv the figures heretofore described the upper strut has a series of holes at each sideof a line passing through the bolts and a relief at each side at 17, the strut being otherwise in the shape of a disk. In the modification of Figures et to 6 I have shown the upper strut 24 as having its outer periphery 1n the form of a complete circle with openings at both sides of adiameter passing through the bolts 25. This leaves a diametrical bridge at 26 for bracing the strut. A bridge 26 at right angles to bridge 26, as shown in Figure 7, and this will be found preferable in some cases, the whole making a cruciform bridge structure combining the parts 26 and 26 to provide increased rigidity'.

\ The rigid brace formed by the bridge and theiparts adjacentthereto is interrupted only by the bolt holes 27 whichaccomrnodate the bolts 25 with a slight clearance. It will be seen that the upper strut thus provides a structure rigid in a direction parallel to the piston pin 14 but adapted to yield slightly in a direction transverse thereto. For limiting the expansion and contraction of the upper end of the skirt the strut has an annular groove on its under? side adapted to. engage an annular flange at 28 on t-he skirt, the tongue 29 produced in forming the groove ou the strut engaging a groove in the skirt between the tongue 28 and the outer periphery of the skirt. This is the only one expedient for producing a secure engagment of the skirt and the strut and I may use other methods such as will be obvious to those skilled in the art.

The head 10 is secured to the skirt 11 by the bolts 25 having heads 30 flush with the upper surface of the piston head and having knurled portions 31 with a press fit in the head.

The skirt is cut away at both sides beneath the piston bearing as shown at 33 and has slots 34 extending from the upper end to a point below the lower part of the piston pin, or otherwise expressed to a point below the mid-length of the skirt. These slots and cut away portions provide space for" the sidewise extension of the tongues formed thereby as above described and permit the skirt to be held against radial extension or contraction by means of the upper strut 24 and a lower strut 19', the latter consisting of a substantially elliptical ring having an elliptical opening. The ends of the ring fit between raised parts 85 on the downwardly extending tongues of the skirt and the strut may be fastened to the parts 35 either permanently or otherwise as desired.

The bolts 25 fit in the holes in the skirt extensions 36 with a considerable clearance and passages 37 lead to such holes from the exterior of lthe piston at Vthe upper end of the skirt, for the purpose of leading excess oil to the interior of the piston.

Various modifications of my device and the parts thereof will be obvious to those skilledin the art and therefore I do not limit myself to what is shown in the drawings and described in the specification but only as indicated inthe appended claims.

Having thus fully described my` said invention, what I claim as new and desire to secure by Letters Patent, is:

1. A piston having a head, a skirt separable therefrom, and a strut between the head and the skirt said strut having means to engage the upper margin of the skirt for limiting the expansion and contraction thereof, substantially as set forth.

2. A piston having a head, a skirt separa!" ble therefrom and longitudinally slitted at its upper end, and a strut closely engaging the inner surface of the skirt at its upper margin to prevent contraction thereof, Substantially as set forth.

8. A piston having a head, a skirt separa-v ble therefrom and longitudinally slitted at its upper end, a strut closely engaging an inner surface of the skirt at its upper end to prevent contraction thereof said strutbeing in the form of a ring with a bridge extending across the same in line with the piston pin, substantially as set forth.

1i. A piston having a head, `a skirt separable therefrom and longitudinally slitted at its upper end, a strut closely engaging the inner surface of the skirt at its upper end to prevent contraction thereof said strut being in theI form of a ring with a bridge extending accross the saine, substantially as set forth.

5. A piston having a head, a piston pin, a separable skirt having inner extensions forming bearings for the piston pin, bolts connecting the head and the piston pinto the skirt said extensions having openings ittingloosely about the bolts and, one or more oil passages leading to vsaidopeniugs from the upper end of the skirt, substantially as set forth.

l(i. A piston having a head, a skirt separable therefrom, an upwardly extending rim? on the skirt, a `strut fitting closely within the i rim and separating the head and the skirt and a boss on the skirt fitting within an opening of the strutfto aline the head and the skirt, substantially as set forth.

7. A piston having a head, a' skirt separable therefrom having opposed inward extensions, an upwardly extending rim on the skirt, a piston pin, bolts extending upwardly through the piston pin and said extensions on the skirt and engaging threaded openings in the headfand a strut between the head and the skirt fitting closely within the said rim and relieved at .opposite sides adjacent said bolts, substantially as set forth.

8. A piston having a head, a skirt separable therefrom having diametrically opposite inward extensions, bolts passing upward through the piston pin and said extensions into the head for securing the parts together said skirt having slits extendingrespectively from the upper and lower edges past the piston pin, and upper and lower struts to limit the contraction ofthe skirt, substantially as set forth. i

A 9. A piston having a head a skirt separable therefrom having diametrically opposite inward extensions, a piston pin, bolts passing upward through the pistonpin and said extensions into the head for securing the v parts together said skirt having slits extending respectively fromthe upper and lower edges past the piston pin, and upper and lower struts bearing against the interior surface of the skirt to limit its contraction said 'lower strut being in the form of a ring resting againstattend end faces .on the under,

side of the piston pin, substantially as set forth.

10. A piston having ahead, a separable Askirt having'slits extending from its upper and'lower edges past the midlength of the skirt, a strut at its upper end and a strut below such midlength fitting closely against the inner periphery of the skirt to prevent rar-hal .contraction thereof, substantially as set forth. v

11. A piston having a head, a separable' skirt, a strut separating the headand the skirt, 4bolts in a plane passing through the' piston pin connecting the head and the skirt said strut being rigid: in a direction transverse to the piston piu and being relieved" at the sides nearest the piston pin, substantially as set forth. f

12. A piston having a head, a skirt separable therefrom and longitudinally slitted at its upper end, a strut closelyengagmgthe inner surface of the skirt at its -,upper end to prevent `contraction thereof` said strut being in the form of a ring with a `bridge extending' across the same in line with lthe piston pin, substantially as set forth.

13.Y A piston having a head, a skirt separable therefrom and longitudinally slit-ted at its upper end, a strut closely ,engaging the vinner surface of the skirt at its upper end'tov prevent contraction thereof said strut being in the form of a ring with bracin means 1n A the form of a cruciform bridge, su stantially as set forth. y J

14. A piston having a head, a skirt separable therefrom and longitudinally slitted at its upper end, a strut closely engaging the inner surface of the skirt at its upper end to bridge having one member extending across the ring in line with the piston pin and adjacent to said boltsLsub'stantially as setV forth.

16. ln a piston,y a unitary head, a skirt, a unitary piston pin Hattened at its lower side, bolts extending through the pin into the head, and means on said bolts engaging the flat side of the pin to secure it in place, substantially as set forth.

env,

prevent contraction thereof said strut being in the form of a ring with a cruciform 1 another at right angles thereto, substantially Y 17. ln a pistona head, a skirt, a piston pin attened at its lower side, bolts extending through the pin into the head, a datsided annular strut engaging thel flat under side of the pin andthe inside of the skirt,

and means on the bolts engaging the strut to,

hold it in place, substantially 'as 'set forth.

having bosses at opposite sides with trans- 18. ln a piston, a head, a separate sh'rt i verse apertures throughthe skirt, a piston pin in said apertures said skirt being away from said apertures to its lower rim to provide piston pin bearings open at the lower side, and bolts extending through the pin anfd the head to hold the parts together, substantially a's set forth.

19. ln aA piston, a hollow head having bosses at opposite sides, a separate skirt having bosses in line with those on thehead and having transverse apertures at their lower ends, a piston pin, and bolts passing through cut'- the pin and said bosses to hx the pin in place,

substantiallyA as set forth.

20ln a piston, a unitary head, a w

piston pin flattened at its lower side, an In Witness whereof, I have hereunto set independent skirt having bossesA arranged my hand at Indianapolis, Indiana, this 28th 10 between the piston pins and the head, and day of May, A. D. nineteen hundred and bolts extending through the piston pins into twenty-three.

5 threaded engagement with the heads said ADOLPH L. NELSON.

bolts having heads engaging the flattened Witnesses: lower side of the piston pin, substantially as E. W. BRADFORD, set forth.,` f M. L. SHULER. 

